As has already been said this study only looks at a subset of people in higher education. Not all the 300M+ guns in this country are owned by old men, there are a large number of young shooters also. It is probably a statement of the obvious that most of those young gun owners are not at university and if they are will probably major in something more practical than arts and humanities. Therefore I suspect that there is an adequate pool of youth with some backbone. The military seems to be able to find adequate numbers to meet it's needs. I would ask every one this question do you think that today's special forces personnel are any weaker softer and less reliable than their 1940's equivalents?

There have always been some "sensitive" souls in each generation. There is evidence that suggests that in both world wars and in some conflicts before, that most of the actual killing done on the front line was carried out by a relatively small proportion of the soldiers. It is often pointed out that modern training methods have helped to correct this problem. I however think one of the key factors is an all volunteer professional military. One of the problems in both WWs was the use of men who were either conscripted or socially pressured into volunteering to serve. Thus in the huge armies used in those conflicts a significant percentage were probably mentally not made for the warrior lifestyle. The exceptions tending to be those units which were all volunteer creations eg. commandos. I therefore suspect that even in 1940 you could still have found plenty of young university students with fragile personalities. The big difference back then was the lack of any support infrastructure for their sensitivity, no safe spaces or therapy puppies. Today they are permitted to wallow in their mental pain and be rewarded for it, this just makes it more obvious to the rest of us and allows it to persist for longer

"I command ye therefore, upon the peril of your lives, to depart immediately out of this place." - Oliver Cromwell 1653